Snap action device



I 0&. 23, 1945.

C. L. MARTIN SNAP ACTION DEVICE Filed March 23, 1944 git/OW .MARTIN CHARLES L 62 FIG.4.

Oct. 23, 1945. Q M'QWN 2,387,402

SNAP ACTION DEVICE Filed March 25, 1944 2 aSheets-Sheet? FIG.8..

INVENTOR. CHARLES L. MARTIN Z yW-M ATTORNEY Patented Oct. 23,, 1945 SNAP ACTION DEVICE Charles L. Martin, Overland, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a

corporation of Delaware Application March 23, 1944, SerialNo. 527,855

(Cl. Pl-92) p 3 Claims.

Thisinvention relates to snap action devices such as may be advantageously used to control a carburetor fuel cut-off valve.

Where a multiple cylinder internal combustion engine is run on part only .of its cylinders during light loadoperation, as has been previously suggested, it is essentialthat the cut-off valve actquickly, in approaching and leaving its fully closed position, to prevent the supplying of an over leanmixture to the cylinders effected which may cause back firing and burn the valves. In

the well known Carter carburetor, the main fuel jet or orifice is controlled by a metering pin 4 which extends through the top of the fuel bowl and is operated by a pivoted lever connected to the throttle. Where this. carburetor is used with certain multiple cylinder engines, particularly,

where some of the cylinders are to be cut-out for light load running, separate barrels of the carburetorfeed separate groups of cylinders. The metering pin may be conveniently used to cut off the nain fuel supply. to one barrel and the corresponding cylinder group. However, very little space is available for the installation of known types of snap action devices. Moreover, these devices have not been positive in their action and, usually, have been of relatively light construction.

Accordingly, an object of the present invention power requirements of the engine vary.

Another object is to provide a snap action device which positively limits the movement. of the valve while, at the same time, insuring positive multi-cylinder internal combustion engine with intake manifolding and a carburetor applied thereto.

Fig. 2 is a vertical section illustrating a carburetor for application to the above engine.

Fig. 3 is an enlarged detail view showing the 'manual or automatic means.

snap action mechanism just before tripping the valve open.

Fig. 4 is a top view of the structure in Fig. 3.

Fig. 5 is a view similar to Fig. 3, but showing the valve just after tripping open.

Fig. 6 is a view similar to Fig. 5 but showing the shifter at the extreme of its openward movement.

Fig. 7 is a similar view showing the valve just on the point of tripping closed.

Fig. 8 is a similar view showing the shifter at the extreme of its valve closing movement.

Fig. 1 shows an eight cylinder engine in which cylinders l, 2, l and 8 are fed by a manifold branch l0 and cylinders 3, 4, 5 and 6 are fed by a separate manifold branch ll. Atthe centers of these manifold branches there is mounted a dual carburetor, generally indicated at [2, and better shown in Fig. 2.

The carburetor comprises float bowls l4 and I5 within which fuel is maintained at a substantially constant level by means of floats l6 and I1 and the usual needle valve mechanism (not shown). A pair of downdraft mixture barrels are shown at l8 and I9 having air inlets 20 and 2| controlled by a choker valve 22 pivoted on a shaft 23 which may be controlled by any suitable as at 24 to accommodate a partition 25 which extends to the top of the carburetor so that suction applied to one barrel will not affect the other barrel.

Fuel is supplied to each barrel through main metering orifices 21 and 28 and upwardly inclined main nozzles 29 and 30 discharging into primary venturis 3| and 32. The discharge end of bar- 'rel l8, which supplies outer manifold ID, is con-i. trolled by a butterfly throttle valve 35 on a shaft 36 controlled by the usual linkage (not shown) extending to the accelerator pedal in the drivers compartment. The discharge end of barrel I9 is constantly open, no throttle being provided therein.

Metering orifice 21 is controlled by a metering pin 31 connected to a lever 38 pivoted above the top of bow1 l4 and, in turn, connected by a link 39 to an arm 40 on throttle shaft 36. Metering pin 4|, controlling metering orifice 218, is connected at its upper extremity to a U-shaped actuator 42, loosely pivoted on shaft 43 and comprising part of the snap action mechanism to be described hereafter. Pin 4| has a valve forming enlargement 46 for closing orifice 2:8. Shaft 43 is journalled in a stanchion 44 received between the legs of actuator 42 (Fig. 4).

The valve is slit,

Rigidly mounted on shaft 43 is a valve shifter lever 45 which extends in opposite directions from shaft 43. Valve actuator 42 has a pair of fingers 41 and 48 projecting from its outer -arm 49. A pair of coiled springs 50 and connect a pin 52 at the right hand end of shifter lever 45 (Fig. 3) and pins 53 and 54 at the extremities of fingers 411" and 48. A pin 55 projects inwardly from the Opposite end of lever 45. arm of the actuator also has a pair of slots 56 and 51 located just inwardly of fingers 41 and 48.

Inner arm 58 of the U-shaped actuator has a U-shaped lateral extension 59 which receives the upper extremity of metering pin 4| between. en-

largements 60 thereon for actuating the same in both directions.

A pair of locking members 62 and 53 are pivoted on a common stub shaft 64 and constantly urged against the extremity of arm 49 of the actuator by the extremities 65 and 65 of a. torsion spring coiled about shaft 64.

The operation of the mechanism is as follows:

As the: throttle valve is opened from the: fully closed position of Fig. 2-,. to the fully open position, the snap action device moves progressively through the positions in Figs. 8, 3, 5,. 6, and. 'Z.v

Fig. 8 shows the shifter lever 45 fully rotated in the. counterclockwise direction so as to move enlargement 46 on pin 4| against metering orifice 28 and thereby cut ofi the supply of fuel therethrough. Shifter lever 45 can move clockwise totheposition in Fig. 3 without afiecting the metering pin, since locking member 62 remains lodged in slot 55 so as to prevent rotation of the. actuator. During this movement, pin 55 at the left hand end of the shifter lever, moves against locking member 62. and, in Fig. 3, has lifted this lever just to the point of releasing the same from notch 51.. In Fig. 5, locking member 62 has been released from locking engagement with the actuator, and the latter has been shifted clockwise, together with the metering pin 4| by upper tension. spring 5.|,;so as. to quickly and fully open valve 45. Lower locking. member 63 is immediately engaged in slot 56. so as to prevent further rotationv of the actuator. However, the shifting lever 45.- can. continue its clockwise movement to theposition in. Fig. 6, in which upper spring 5| is further stretched. Throttle valve 35 will then be fully opened.

During closing of the throttle, shifting lever 45- moves. counterclockwise to the position in Fig. 7, which shows spring 50 tensioned and member 63 just on the point of release from notch 56. In starting position. in 8, lockingmember 53. has

released the actuator, for snap movement in a.

cdunterclockwise direction by springl5|1 so as to fully close valve 461, and. upper locking member 62 is. re-seated in notch 51.

The outer The device, therefore, is positive in its action in both directions as to the extent of movement of the valve and as to the exact point during the throttle movement when shifting occurs. The valve is always either fully opened or fully closed so that there can be no period when an excessive'ly lean mixture is supplied through barrel l9 to the inner group of cylinders. The device, further, is rugged, compact and simple of construction. Various modifications may be made as will occur to those skilled in the art and the exclusive use of. all modifications as come within the scope of the appended claims is contemplated.

I claim:

I. A. snap action device comprising anactuator element and'a shifter element pivoted on a common shaft, spring means connecting said elements, and locking members pivoted on a common shaft eccentric of said first shaft and normally urged, one at a time, into locking. engagement. with. said actuator element, said shifter ele ment'having a part movable. between said locking members and disposed to engage the same, respectively, at spaced points in the shifter stroke, to release the same from saidactuator and permit shifting of the latter by said spring, means.

2; A snap action device comprising an actuator disk and a shifter lever pivoted on a common shaft, spring means resisting relative rotation between said disk and. lever, said disk having matches at spaced points on its periphery, and.

locking detents normally urged against the edge of said disk and positioned. to selectively enter said notches during the rotation of said disk" to lock the same, said shifter lever having a projection disposed-to selectively engage said locking detents near the ends of the normal stroke of said shifter to remove the same from looking relationship with said diskso as to release said disk for shifting-by said spring means.

3. A snapaction device comprisingan actuator disk and ashifter lever pivotedon a common shaft, spring means between said disk and: lever resisting relative movements in opposite direc- 3 tions thereof, a pair of locking detents havinga. common pivotal mounting eccentric of the pivot of said disk and lever spring means normally urging said detents against the adjacent edge of said disk, said detents being disposed to selectively enter said notches attheends of the normal stroke-ofsaid actuator, and saidshifter lever having'aprojection between said' detents positioned toselectively engage the same as said-- shifter approaches the ends of its. stroke. to Withdraw the detent' from. locking relationship with said disk and thereby release said. disk for movement by said spring means.

CHARLES L. 

